A modified epoxy adhesive for snowboards and its preparation method

Abstract

The present invention relates to the field of adhesives, and discloses a modified epoxy adhesive for snowboards and a preparation method thereof. The modified epoxy adhesive for snowboards comprises: modified epoxy resin, modified graphene oxide, curing agent, toughening agent, and diluent; the modified epoxy resin is prepared by grafting an epoxy resin with a carboxyl-terminated modifier, wherein the carboxyl-terminated modifier is prepared by reacting phenylphosphonic dichloride with 2-(hydroxymethyl)aminoethanol, grafting octenyl succinic anhydride, and further reacting with glutaric acid; the modified graphene oxide is prepared by functionalizing graphene oxide with lysine, and grafting the functionalized graphene oxide after reacting allyl glycidyl ether with polymethylhydrosiloxane. By adding the modified epoxy resin and the modified graphene oxide, the present invention endows the adhesive with excellent mechanical properties and bonding properties, has high toughness under normal and low temperature conditions, and improves the water resistance and flame retardancy at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of adhesives, and particularly relates to a modified epoxy adhesive for snowboards and a preparation method thereof. Background Art

[0002] A snowboard is a sports equipment for skiing. During the preparation of a snowboard, an epoxy adhesive is generally used for bonding heterogeneous materials such as wood, fiber, plastic, and metal. After uniformly mixing the resin and the curing agent, under manual conditions, the glue is applied layer by layer in the order of the bottom of the board, high-performance fiber, wood core, and the surface of the board. Then, under certain pressure and temperature conditions, the composite snowboard is fixed in a specific mold to achieve the bonding of the interlayer materials.

[0003] The performance of the epoxy adhesive is affected by environmental factors. It is prone to degradation under the influence of humidity and temperature environments. When it is exposed to a humid environment, water molecules easily invade through the microcracks and pores in the epoxy adhesive, causing plasticization of the adhesive material, resulting in irreversible cracking, reducing the mechanical properties, and causing premature peeling failure at the bonding interface. In addition, when the epoxy adhesive is used in a low-temperature environment, the cross-linked network structure of the resin molecules is frozen and concentrated, leading to a further increase in the brittleness of the resin, a significant reduction in its impact resistance and toughness, and often causing cracking of the epoxy resin in the alternating environment of normal and low temperatures, restricting its application. Summary of the Invention

[0004] To solve the deficiencies mentioned in the above background art, the purpose of the present invention is to provide a modified epoxy adhesive for snowboards and a preparation method thereof. By adding modified epoxy resin and modified graphene oxide, the adhesive is given excellent mechanical properties and bonding properties, with high toughness under normal and low-temperature conditions, and at the same time, the water resistance and flame retardancy are improved.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A modified epoxy adhesive for snowboards, comprising the following components in parts by weight: 70-90 parts of modified epoxy resin, 15-20 parts of modified graphene oxide, 15-30 parts of curing agent, 2-5 parts of toughening agent, and 10-20 parts of diluent;

[0007] The modified epoxy resin is prepared by grafting an epoxy resin with a carboxyl-terminal modifier, wherein the carboxyl-terminal modifier is prepared by carrying out a substitution reaction between phenylphosphoryl dichloride and 2-(hydroxymethyl)aminoethanol, grafting octenyl succinic anhydride, and further carrying out a polycondensation reaction with glutaric acid; the modified graphene oxide is prepared by functionalizing graphene oxide with lysine, and grafting the functionalized graphene oxide after carrying out a hydrosilylation reaction between allyl glycidyl ether and polymethylhydrosiloxane.

[0008] Preferably, the epoxy resin is one of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0009] Preferably, the toughening agent is SEBS; the curing agent is one or a combination of more than one of aliphatic amine curing agent, cycloaliphatic amine curing agent, aromatic amine curing agent, polyetheramine curing agent, and polyamide curing agent; the diluent is one or a combination of more than one of ethylene glycol diglycidyl ether, dodecyl glycidyl ether, benzyl glycidyl ether, and neopentyl glycol diglycidyl ether.

[0010] Preferably, the preparation method of the modified graphene oxide includes the following steps:

[0011] (1) Take allyl glycidyl ether in a reactor, heat up to 105 - 120 °C, introduce nitrogen and keep warm for 20 - 30 min, cool down to 75 - 85 °C, add chloroplatinic acid catalyst and polymethylhydrosiloxane, and react at 105 - 120 °C for 3 - 5 h to prepare an epoxy group organosilicon monomer.

[0012] (2) Take graphene oxide and ultrasonically disperse it in deionized water to obtain a dispersion. Take lysine and dissolve it in deionized water, adjust the pH value to 7 - 7.5 with sodium hydroxide solution, then add the dispersion and mix evenly, and react at 30 - 45 °C for 18 - 24 h. After the reaction is completed, wash and dry to prepare functionalized graphene oxide.

[0013] (3) Take the functionalized graphene oxide and ultrasonically disperse it in acetone, add the epoxy group organosilicon monomer and triphenylphosphine, and react at 85 - 105 °C for 12 - 16 h. After the reaction is completed, filter, wash, and dry to prepare the modified graphene oxide.

[0014] Preferably, in step (3), the mass ratio of the functionalized graphene oxide to the epoxy group organosilicon monomer is 1:0.4 - 0.7.

[0015] Preferably, the preparation method of the modified epoxy resin includes the following steps:

[0016] A. Take phenylphosphoryl dichloride and 2-(hydroxymethylamino)ethanol in a reactor, add tetrahydrofuran solvent and stir to react for 5 - 7 h. During the reaction, add triethylamine in batches to remove the hydrogen chloride generated by the reaction. After the reaction is completed, carry out suction filtration, rotary evaporation, and drying to prepare a hydroxyl-terminated intermediate.

[0017] B. Take the hydroxyl-terminated intermediate, octenyl succinic anhydride, p-toluenesulfonic acid, and N,N-dimethylformamide in a reactor, and stir to react at 110 - 125 °C for 4 - 6 h. After the reaction is completed, carry out vacuum distillation and drying to prepare a modified hydroxyl-terminated intermediate.

[0018] C. Take the modified hydroxy - terminated intermediate and glutaric acid in a reactor, place it at 120 - 135 °C and stir - react for 5 - 7 h. After the reaction is completed, take out the product and dry it to prepare the carboxyl - terminated modifier;

[0019] D. Take the carboxyl - terminated modifier and epoxy resin in a reactor, place it at 100 - 120 °C and stir - react for 5 - 6 h. After the reaction is completed, take out the product and dry it to prepare the modified epoxy resin.

[0020] Preferably, in the step A, the molar ratio of phenylphosphoryl dichloride to 2 - (hydroxymethyl) aminoethanol is 1:2 - 2.6.

[0021] Preferably, in the step B, the molar ratio of the hydroxy - terminated intermediate to octenyl succinic anhydride is 1:2 - 2.5.

[0022] Preferably, in the step C, the molar ratio of the modified hydroxy - terminated intermediate to glutaric acid is 1:1.3 - 1.5.

[0023] The preparation method of the modified epoxy adhesive for snowboards as described above includes the following steps:

[0024] S1. Take the weight parts of the modified epoxy resin and the toughening agent, mix them and pre - heat at 60 - 80 °C for 20 - 30 min to prepare a premix;

[0025] S2. Add the weight parts of modified graphene oxide, curing agent and diluent to the premix and stir evenly to prepare a mixture;

[0026] S3. Transfer the mixture to a grinder for grinding and dispersion, and then defoam in a vacuum environment for 20 - 60 min to prepare the modified epoxy adhesive.

[0027] The beneficial effects of the present invention:

[0028] The present invention utilizes the hydrosilylation reaction of allyl glycidyl ether and polymethylhydrosiloxane to prepare an epoxy-functionalized organosilicon monomer. Meanwhile, the present invention utilizes the reaction between the carboxyl groups in the graphene oxide structure and the amino groups in the lysine structure to prepare functionalized graphene oxide. Then, the epoxy groups in the epoxy-functionalized organosilicon monomer structure react with the carboxyl groups in the functionalized graphene oxide structure to prepare modified graphene oxide. Among them, graphene oxide, as a nano-filler, has the advantages of impermeability to oxygen and water and a high specific surface area. Grafting the epoxy-functionalized organosilicon monomer between the layers of graphene oxide can not only increase the layer spacing of graphene oxide, making the transmission paths of oxygen and water tortuous, but also increase the contact area between graphene oxide and epoxy resin, improving the compatibility between the modified graphene oxide and epoxy resin. Moreover, epoxy resin can be co-cured with the modified graphene oxide and the curing agent, enhancing the crosslinking density and improving the waterproof and toughening effects. In addition, the grafting of the epoxy-functionalized organosilicon monomer introduces Si-O-Si flexible chain segments, forming a network structure with more free volume, reducing the stress concentration in the cured product, and thus enhancing the toughness of the epoxy resin adhesive at both normal and low temperatures.

[0029] The present invention utilizes the substitution reaction between the chlorine atoms in the phenylphosphoryl dichloride structure and the hydroxyl groups in the 2-(hydroxymethylamino)ethanol structure to prepare a hydroxyl-terminated intermediate containing phosphorus and nitrogen elements, thereby enhancing the flame retardancy of the adhesive. Then, the -NH group in the hydroxyl-terminated intermediate structure undergoes a grafting reaction with the anhydride group in the hydrophobic substance octenyl succinic anhydride structure to prepare a modified hydroxyl-terminated intermediate, thereby enhancing the hydrophobicity of the adhesive. Further, the polyesterification reaction of glutaric acid with the hydroxyl-terminated intermediate is used to prepare a carboxyl-terminated modifier with carboxyl groups at both ends. Then, its carboxyl groups react with the epoxy groups in the epoxy resin structure to prepare a modified epoxy resin. The grafting of the carboxyl-terminated modifier introduces flexible chains, hydrophobic long chains, phosphorus atoms, and nitrogen atoms into the three-dimensional network structure of the epoxy resin, achieving the effects of toughening, improving water resistance, and flame retardancy. Detailed implementation manners

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] Example 1 A method for preparing modified graphene oxide includes the following steps:

[0032] (1) Take 180 g of allyl glycidyl ether in a reactor, heat it up to 110 °C, introduce nitrogen and keep it warm for 30 min, then cool it down to 80 °C, add 280 μL of chloroplatinic acid catalyst and 363 g of polymethylhydrogensiloxane, and react at 110 °C for 5 h to prepare an epoxy group-containing silicone monomer.

[0033] (2) Take 1 g of graphene oxide and ultrasonically disperse it in 160 mL of deionized water to obtain a dispersion. Take 2.5 g of lysine and dissolve it in 40 mL of deionized water, and adjust the pH value to 7.4 with a 4 mg / mL sodium hydroxide solution, then add the dispersion and mix evenly, and react at 40 °C for 20 h. After the reaction is completed, wash and dry it to prepare functionalized graphene oxide.

[0034] (3) Take 1 g of functionalized graphene oxide and ultrasonically disperse it in 40 mL of acetone, add 0.5 g of epoxy group-containing silicone monomer and 0.002 g of triphenylphosphine, and react at 95 °C for 14 h. After the reaction is completed, filter, wash and dry it to prepare modified graphene oxide.

[0035] Example 2 A preparation method of a modified epoxy resin includes the following steps:

[0036] A. Take 19.5 g of phenylphosphonic dichloride and 22.8 g of 2-(hydroxymethylamino)ethanol in a reactor, add 100 mL of tetrahydrofuran solvent and stir to react for 6 h. During the reaction, add triethylamine in batches to remove the hydrogen chloride generated by the reaction. After the reaction is completed, filter by suction, rotary evaporate and dry to prepare a hydroxyl-terminated intermediate.

[0037] B. Take 30.4 g of the hydroxyl-terminated intermediate, 46.3 g of octenyl succinic anhydride, 0.45 g of p-toluenesulfonic acid and 100 mL of N,N-dimethylformamide in a reactor, and stir to react at 120 °C for 6 h. After the reaction is completed, carry out vacuum distillation and dry to prepare a modified hydroxyl-terminated intermediate.

[0038] C. Take 28.9 g of the modified hydroxyl-terminated intermediate and 6.87 g of glutaric acid in a reactor, and stir to react at 125 °C for 6 h. After the reaction is completed, take out the product and dry it to prepare a carboxyl-terminated modifier.

[0039] D. Take 15.2 g of the carboxyl-terminated modifier and 30.4 g of epoxy resin CYD-128 in a reactor, and stir to react at 120 °C for 6 h. After the reaction is completed, take out the product and dry it to prepare a modified epoxy resin.

[0040] Example 3 A modified epoxy adhesive for snowboards, comprising the following components in parts by weight: 72 parts of the modified epoxy resin prepared in Example 2, 15 parts of the modified graphene oxide prepared in Example 1, 15 parts of the curing agent diaminodiphenylmethane, 2 parts of the toughening agent SEBS, and 12 parts of the diluent ethylene glycol diglycidyl ether.

[0041] The preparation method of the above-mentioned modified epoxy adhesive for snowboards comprises the following steps:

[0042] S1. Take the modified epoxy resin and toughening agent in parts by weight, mix them and preheat at 75 °C for 30 min to obtain a premix.

[0043] S2. Add the modified graphene oxide, curing agent, and diluent in parts by weight to the premix and stir evenly to obtain a mixture.

[0044] S3. Transfer the mixture to a grinder for grinding and dispersion, and then defoam in a vacuum environment for 30 min to obtain the modified epoxy adhesive.

[0045] Example 4 A modified epoxy adhesive for snowboards, comprising the following components in parts by weight: 80 parts of the modified epoxy resin prepared in Example 2, 17 parts of the modified graphene oxide prepared in Example 1, 22 parts of the curing agent diaminodiphenylmethane, 4 parts of the toughening agent SEBS, and 16 parts of the diluent ethylene glycol diglycidyl ether.

[0046] The preparation method of the above-mentioned modified epoxy adhesive for snowboards is the same as that of Example 3.

[0047] Example 5 A modified epoxy adhesive for snowboards, comprising the following components in parts by weight: 88 parts of the modified epoxy resin prepared in Example 2, 20 parts of the modified graphene oxide prepared in Example 1, 28 parts of the curing agent diaminodiphenylmethane, 5 parts of the toughening agent SEBS, and 20 parts of the diluent ethylene glycol diglycidyl ether.

[0048] The preparation method of the above-mentioned modified epoxy adhesive for snowboards is the same as that of Example 3.

[0049] Comparative Example 1 A modified epoxy adhesive for snowboards, comprising the following components in parts by weight: 88 parts of the epoxy resin CYD-128, 20 parts of the modified graphene oxide prepared in Example 1, 28 parts of the curing agent diaminodiphenylmethane, 5 parts of the toughening agent SEBS, and 20 parts of the diluent ethylene glycol diglycidyl ether.

[0050] The preparation method of the above-mentioned modified epoxy adhesive for snowboards is the same as that of Example 3.

[0051] Comparative Example 2 A modified epoxy adhesive for snowboards, comprising the following components in parts by weight: 88 parts of the modified epoxy resin prepared in Example 2, 20 parts of graphene oxide, 28 parts of curing agent diaminodiphenylmethane, 5 parts of toughening agent SEBS, and 20 parts of diluent ethylene glycol diglycidyl ether.

[0052] The preparation method of the above-mentioned modified epoxy adhesive for snowboards is the same as that of Example 3.

[0053] Performance testing

[0054] The modified epoxy adhesives prepared in Examples 3 - 5 and Comparative Examples 1 - 2 were used to bond and fix the PU film material on the snowboard surface and the P-Tex board material on the bottom of the board fixed to the fixture, and cured at 0.2 MPa and 75 °C for 40 min for performance testing. The data results are shown in Table 1.

[0055] Table 1 Test results of sample performance

[0056] Group Items Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Tensile Strength / MPa 72.4 76.3 78.7 66.8 51.2 Impact Strength (KJ / m-2) 28.8 29.2 29.6 22.7 17.4 Impact Strength at -20°C (KJ / m-2) 26.6 27.1 27.2 20.1 11.2 Peel Strength of Surface Material of the Plate (KN / m) 2.3 2.7 2.5 2.3 2.1 Peel Strength of Bottom Material of the Plate (KN / m) 3.4 3.9 3.7 3.6 3.2 Peel Strength of Surface Material of the Plate at -20°C (KN / m) 2.0 2.5 2.2 2.0 1.6 Peel Strength of Bottom Material of the Plate at -20°C (KN / m) 3.1 3.7 3.5 3.2 2.4 Water Contact Angle / ° 94.5 95.2 97.8 71.2 95.7 Limiting Oxygen Index / % 29.2 30.6 32.2 25.6 30.2

[0057] It can be seen from the data in Table 1 that the modified epoxy adhesives prepared in Examples 3 - 5 of the present invention have excellent mechanical properties and bonding properties, high toughness under normal and low temperature conditions, and improved water resistance and flame retardancy. Among them, in Comparative Example 1, the epoxy resin was not modified, and the measured tensile strength, impact strength, water contact angle, and limiting oxygen index changed significantly compared with Examples 3 - 5. The reason is that flexible chains, hydrophobic long chains, phosphorus atoms, and nitrogen atoms were not introduced into the three-dimensional network structure of the epoxy resin, resulting in a decrease in its performance. In Comparative Example 2, the graphene oxide was not modified, and the measured tensile strength, impact strength under normal and low temperature conditions, and peel strength under low temperature conditions were lower than those in Examples 3 - 5, indicating that modifying the graphene oxide can improve the mechanical properties and low temperature resistance of the adhesive.

[0058] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0059] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A modified epoxy adhesive for a snowboard, characterized in that: The invention comprises the following components in parts by weight: 70-90 parts of modified epoxy resin, 15-20 parts of modified graphene oxide, 15-30 parts of curing agent, 2-5 parts of toughening agent and 10-20 parts of diluent; The modified epoxy resin is prepared by grafting a terminal carboxyl modifier with an epoxy resin, wherein the terminal carboxyl modifier is prepared by grafting octenyl succinic anhydride with phenylphosphoryl dichloride and 2-hydroxymethylaminoethanol, and further undergoing polyesterification reaction with glutaric acid; the modified graphene oxide is prepared by functionalizing graphene oxide with lysine, and grafting functionalized graphene oxide with allyl glycidyl ether and polymethyl hydrogen siloxane after a silylation reaction; The preparation method of the modified graphene oxide comprises the following steps: (1) Allyl glycidyl ether was placed in a reactor, heated to 105-120°C, nitrogen was introduced and kept warm for 20-30 min, cooled to 75-85°C, chloroplatinic acid catalyst and polymethylhydrogensiloxane were added, and the mixture was reacted at 105-120°C for 3-5 h to prepare an epoxy silicone monomer; (2) ultrasonically dispersing graphene oxide in deionized water to obtain a dispersion, dissolving lysine in deionized water, adjusting the pH value to 7-7.5 with a sodium hydroxide solution, then adding the dispersion to mix evenly, placing at 30-45° C. for reaction for 18-24 hours, and washing and drying after the reaction to obtain functionalized graphene oxide; (3) ultrasonically dispersing the functionalized graphene oxide in acetone, adding epoxy silicone monomer and triphenylphosphine, and reacting at 85-105°C for 12-16 hours. After the reaction is completed, filtering, washing, and drying to obtain modified graphene oxide; The preparation method of the modified epoxy resin comprises the following steps: A. Phenylphosphoryl dichloride and 2-hydroxymethylaminoethanol are placed in a reactor, tetrahydrofuran solvent is added, and the reaction is stirred for 5 to 7 hours. During the reaction, triethylamine is added in batches to remove the hydrogen chloride produced by the reaction. After the reaction is completed, the terminal hydroxyl intermediate is prepared by suction filtration, rotary evaporation, and drying; B. Place the terminal hydroxyl intermediate, octenyl succinic anhydride, p-toluenesulfonic acid and N,N-dimethylformamide in a reactor, stir and react at 110-125° C. for 4-6 hours, and after the reaction is completed, perform vacuum distillation and drying to obtain a modified terminal hydroxyl intermediate; C. Take the modified terminal hydroxyl intermediate and glutaric acid in a reactor, place it at 120-135° C. and stir to react for 5-7 hours. After the reaction is completed, take out the product and dry it to prepare a terminal carboxyl modifier; D. Place the terminal carboxyl modifier and epoxy resin in a reactor, place them at 100-120°C and stir to react for 5-6 hours. After the reaction is completed, take out the product and dry it to prepare a modified epoxy resin.

2. The modified epoxy adhesive for snowboard according to claim 1, characterized in that: The epoxy resin is one of bisphenol A epoxy resin and bisphenol F epoxy resin.

3. The modified epoxy adhesive for snowboard according to claim 1, characterized in that: The toughening agent is SEBS; the curing agent is one or more combinations of aliphatic amine curing agent, alicyclic amine curing agent, aromatic amine curing agent, polyether amine curing agent, and polyamide curing agent; the diluent is one or more combinations of ethylene glycol diglycidyl ether, dodecyl glycidyl ether, benzyl glycidyl ether, and neopentyl glycol diglycidyl ether.

4. The modified epoxy adhesive for snowboard according to claim 1, characterized in that: In the step (3), the mass ratio of the functionalized graphene oxide to the epoxy silicone monomer is 1:0.4-0.

7.

5. The modified epoxy adhesive for snowboard according to claim 1, characterized in that: In the step A, the molar ratio of phenylphosphoryl dichloride to 2-hydroxymethylaminoethanol is 1:2-2.

6.

6. The modified epoxy adhesive for snowboard according to claim 1, characterized in that: In the step B, the molar ratio of the terminal hydroxyl intermediate to octenyl succinic anhydride is 1:2-2.

5.

7. The modified epoxy adhesive for snowboard according to claim 1, characterized in that: In the step C, the molar ratio of the modified terminal hydroxyl intermediate to glutaric acid is 1:1.3-1.

5.

8. A method for preparing a modified epoxy adhesive for a snowboard according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, taking parts by weight of modified epoxy resin and toughening agent, mixing them and preheating them at 60-80° C. for 20-30 min to prepare a premix; S2, adding parts by weight of modified graphene oxide, a curing agent, and a diluent to the premix and stirring evenly to prepare a mixture; S3. The mixture is transferred to a grinder for grinding and dispersion, and then degassed in a vacuum environment for 20 to 60 minutes to prepare a modified epoxy adhesive.